GitHub Enterprise Server up to 3.21.3 Manage API server-side request forgery

Summaryinfo

A vulnerability identified as critical has been detected in GitHub Enterprise Server up to 3.17.18/3.18.12/3.19.9/3.20.5/3.21.3. This impacts an unknown function of the component Manage API. This manipulation causes server-side request forgery. This vulnerability is registered as CVE-2026-18730. Remote exploitation of the attack is possible. No exploit is available.

Detailsinfo

A vulnerability classified as critical was found in GitHub Enterprise Server up to 3.17.18/3.18.12/3.19.9/3.20.5/3.21.3. Affected by this vulnerability is some unknown functionality of the component Manage API. The manipulation with an unknown input leads to a server-side request forgery vulnerability. The CWE definition for the vulnerability is CWE-918. The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

A server-side request forgery (SSRF) vulnerability was identified in GitHub Enterprise Server that allowed an unauthenticated attacker to cause the Manage API to send crafted outbound requests to an attacker-controlled host. An unauthenticated endpoint parsed an attacker-supplied cluster configuration and issued gateway-to-agent requests whose HMAC authenticated only a timestamp, not the request path or body. An attacker positioned to intercept the outbound request could capture this token and replay it against privileged management agent endpoints. High-availability deployments were not affected due to a topology restriction. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.22 and was fixed in versions 3.17.19, 3.18.13, 3.19.10, 3.20.6, and 3.21.4. This vulnerability was reported via the GitHub Bug Bounty program.

The advisory is shared at docs.github.com. This vulnerability is known as CVE-2026-18730 since 08/03/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Neither technical details nor an exploit are publicly available.

Upgrading to version 3.17.19, 3.18.13, 3.19.10, 3.20.6 or 3.21.4 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-69714). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Type

• Bug Tracking Software

Vendor

• GitHub

Name

• Enterprise Server

Version

• 3.17.0
• 3.17.1
• 3.17.2
• 3.17.3
• 3.17.4
• 3.17.5
• 3.17.6
• 3.17.7
• 3.17.8
• 3.17.9
• 3.17.10
• 3.17.11
• 3.17.12
• 3.17.13
• 3.17.14
• 3.17.15
• 3.17.16
• 3.17.17
• 3.17.18
• 3.18.0
• 3.18.1
• 3.18.2
• 3.18.3
• 3.18.4
• 3.18.5
• 3.18.6
• 3.18.7
• 3.18.8
• 3.18.9
• 3.18.10
• 3.18.11
• 3.18.12
• 3.19.0
• 3.19.1
• 3.19.2
• 3.19.3
• 3.19.4
• 3.19.5
• 3.19.6
• 3.19.7
• 3.19.8
• 3.19.9
• 3.20.0
• 3.20.1
• 3.20.2
• 3.20.3
• 3.20.4
• 3.20.5
• 3.21.0
• 3.21.1
• 3.21.2
• 3.21.3

License

• open-source

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Discussion